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<table width="100%" summary="page for SiegelsEx"><tr><td>SiegelsEx</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Siegel's Exact Fit Example Data</h2>

<h3>Description</h3>

<p>A small counterexample data set devised by Andrew Siegel.
Six (out of nine) data points lie on the line <i>y = 0</i> such that
some robust regression estimators exhibit the &ldquo;<em>exact fit</em>&rdquo;
property.
</p>


<h3>Usage</h3>

<pre>data(SiegelsEx, package="robustbase")</pre>


<h3>Format</h3>

<p>A data frame with 9 observations on the following 2 variables.
</p>

<dl>
<dt><code>x</code></dt><dd><p>a numeric vector</p>
</dd>
<dt><code>y</code></dt><dd><p>a numeric vector</p>
</dd>
</dl>



<h3>Source</h3>

<p>Emerson and Hoaglin (1983, p.139)
</p>


<h3>References</h3>

<p>Peter J. Rousseeuw and Annick M. Leroy (1987)
<em>Robust Regression and Outlier Detection</em> Wiley, p.60&ndash;61
</p>


<h3>Examples</h3>

<pre>
data(SiegelsEx)
plot(SiegelsEx, main = "Siegel's example for 'exact fit'")
abline(          lm(y ~ x, data = SiegelsEx))
abline(MASS::lqs(y ~ x, data = SiegelsEx, method = "lms"), col = 2)
legend("topright", leg = c("lm", "LMS"), col=1:2, lwd=1, inset = 1/20)
</pre>


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